VB.Net, text file operations help

[murderdoll]

Hello,

Here is the scenario, let's say I have the following XML file:

<updates>

<update date="2-2-2002" version="0.1" file="Updates\0.1.xml"></update>

<update date="5-5-2002" version="0.2" file="Updates\0.2.xml"></update>

<update date="6-5-2002" version="0.3" file="Updates\0.3.xml"></update>

<update date="6-5-2002" version="0.4" file="Updates\0.4.xml"></update>

<update date="6-5-2002" version="0.5" file="Updates\0.5.xml"></update>

</updates>

I want to generate a list of the "file" attribute contents from let's say 0.3 -> 0.5: ( I shall input 0.3,0.4,0.5 to the program I'm making, and it auto generates the content I need )

Updates\0.3.xml

Updates\0.4.xml

Updates\0.5.xml

What's the easiest way to do that ?

p.s: if i were to generate an updates list of all lines inside the xml file, it would be easy, but i'm looking for specific lines.

[Antaris Veteran]

Hi,

.NET does provide a series of classes for dealing with xml. What you could do, is create a function which opens the xml document (either with a quick xml reader, or with an xml document, which allows you to query the xml using xpath) and produces a list of string items:

Public Function GetFileList(ByVal xmlSourceFile As String, ByVal rangeStart As Double, ByVal rangeEnd As Double) As List(Of String)
	Dim document As New Xml.XmlDocument()
	document.Load(xmlSourceFile)
	Dim list = New List(Of String)

	For Each node As Xml.XmlNode In document.SelectNodes("//updates/update")
		Dim version As Double
		If (Double.TryParse(node.Attributes("version").Value, version)) Then
			If (version >= rangeStart And version <= rangeEnd) Then
				list.Add(node.Attributes("file").Valuef
		End If
	Next

	list.Sort()
	Return list
End Function

[Rob Veteran]

Damn Antaris, got there just before me!

[Antaris Veteran]

You mean like, half an hour? Damn that was close :p

[Rob Veteran]

Ha I was in a supermarket when I read it on my phone, and was going to reply when I came back :p

[Antaris Veteran]

Good to see you're Neowining on the road ;)

[murderdoll]

Sweet... Thanks a lot Antaris, worked like a charm :p

[Antaris Veteran]

No probs mate :)

[murderdoll]

I'm having a little bit of a problem

Dim file As String = System.Windows.Forms.Application.StartupPath + "\tempupdates.xml"

		stringlist = determine.GetFileList(file, ok(0), ok(1))

after I pass the tempupdates.xml file through the function, I try to delete the file using code ( System.IO.File.Delete(System.Windows.Forms.Application.StartupPath + "\tempupdates.xml") ) , but it says that it can't delete it because the file is in use.

( Trying to delete it after the function exits )

Any idea?

Edit: Actually nevermind, I commented some other functions and the delete function is working now... I think some other function is keeping the file in use.

edit2: nevermind about this, all fixed.. StreamReaders wasn't closed at their right positions :o

Edited March 8, 2009 by murderdoll

[Antaris Veteran]

Just remember, when you open a file, you must explicitly close it, otherwise a lock is kept active on the file.

[boogerjones]

I'm not sure if this will fix the file-access problem, but it might.

Instead of assigning streamReaders like this:

Dim sr As IO.StreamReader = IO.File.OpenText(file2)

do this instead:

Dim sr As New StreamReader(New FileStream(file2, FileMode.Open))